1. Field of the Invention
This invention relates to lead frames and lead frame leads and, more specifically, to such lead frame leads that are reinforced.
2. Brief Description of the Prior Art
Prior art semiconductor packages generally include an encapsulant, generally plastic, within which is disposed a thin flat lead frame having thin flat leads extending out of the package. A semiconductor chip is secured to the lead frame with wires bonded between pads on the chip and the thin flat leads of the lead frame, all within the encapsulant. The thin flat leads that extend from the encapsulant and form a part of the package are generally connected to printed circuit boards or the like, generally by soldering. In order to make such connections, it is necessary that the thin flat leads be present and it is also necessary that the thin flat leads be sufficiently rigid to lie against the surface to which they are to be attached or connected.
With the present move toward ever thinner semiconductor packages, it has become essential that the lead frames utilized in the fabrication of such thinner semiconductor packages also become thinner. Due to this thinning of the lead frames, the flat leads extending out of the encapsulant and even the body of the lead frame itself have displayed a tendency not to lie flat during packaging. This failure to lie flat has also caused a problem during a later attachment operation because the thin flat leads extending out of the encapsulant are not sufficiently rigid to insure that they remain in contact with the surface to which they are to be attached. This causes a problem during, for example, a soldering operation in that the solder is often unable to secure the lead to the surface to which it is to be soldered. In addition, the flat leads have also had a tendency to break off, thereby resulting in a yield loss for this reason as well.